Field of the Invention
The present invention relates to a toner to be used in, for example, an electrophotographic method, an electrostatic recording method, or a magnetic recording method, and a method of producing the toner.
Description of the Related Art
A printer or a copying machine needs to be excellent in reproducibility of a latent image and to have a high resolution. At the same time, the downsizing of a main body of any such apparatus and such stability of an image that the quality of the image does not change even when the apparatus is used for a long time period irrespective of its use environment have been required.
First, an approach to realizing the downsizing of the main body is, for example, the downsizing of a printer constituent member or the elimination of the member. One example of the approach is the compacting of a toner-storing portion, such as a cartridge. A reduction in toner consumption per page has been strongly required for the downsizing of the toner-storing portion. To that end, it is important that a latent image be developed with a just enough amount of a toner. An effective method for the reduction in toner consumption is a one-component contact developing system involving pressing a developer carrying member against the surface of an electrostatic latent image-bearing member (photosensitive member) to perform the development.
In a conventional one-component contact developing system, the developer carrying member and a developer-supplying member are stored in a developing device. The elimination of the developer-supplying member enables not only the reduction in toner consumption but also additional compacting of the toner-storing portion. In addition, the elimination of a cleaning blade, such as an elastic rubber blade, configured to clean out a toner remaining on the photosensitive member without being transferred onto a transfer material after transfer (transfer residual toner) leads to additional compacting of the cartridge.
However, when such developer-supplying member is not used, the stabilization of image quality at the time of long-term use becomes a problem. In particular, a difference between developability after black image output and that after white image output in a low-temperature and low-humidity environment, i.e., a so-called developing ghost is a problem. In addition, there occurs a problem in that the transfer residual toner is continuously sandwiched in a gap between the developer carrying member and the photosensitive member, i.e., a so-called development nip owing to the long-term use to be compressed, thereby melt-adhering onto the photosensitive member (hereinafter referred to as “melt adhesion to the photosensitive member”).
In the following documents, various approaches from the toner have been performed for such stabilization of the image quality at the time of the long-term use independent of a use environment.
In Japanese Patent Application Laid-Open No. 2008-145652, there is proposed a toner in which the state of adhesion of hydrophobic silica having an average particle diameter of from 30 nm to 100 nm is controlled by an external addition step.
In Japanese Patent Application Laid-Open No. 2009-229785, there is proposed a toner for developing an electrostatic latent image, having a ratio HH/HL of its saturated water content HH under high-temperature and high-humidity conditions (30° C. and 95% RH) to its saturated water content HL under low-temperature and low-humidity conditions (10° C. and 15% RH) falling within a range of 1.50 or less.
In Japanese Patent Application Laid-Open No. 2012-63636, there is disclosed a method of producing a toner in which the states of adhesion of particles having an average primary particle diameter of 100 nm or more and 1 μm or less are controlled by an external addition apparatus.
In Japanese Patent Application Laid-Open No. 2011-197371, there is proposed a toner in which: an external additive having a particle diameter of less than 100 nm is fixed to the surface of a toner base particle; and an external additive having a particle diameter of 100 nm or more and 500 nm or less is adhered to the surface of the toner base particle so as to be capable of being liberated.
In Japanese Patent Application Laid-Open No. 2014-81573, there is proposed a toner in which the amounts of large-particle diameter hydrophobic silica having a particle diameter of from 80 nm to 500 nm, medium-particle diameter hydrophobic silica having a particle diameter of from 20 nm to 70 nm, and small-particle diameter hydrophobic silica having a particle diameter of from 5 nm to 15 nm to be added to a toner particle containing a bioplastic resin are adjusted.